FRESNO -- Authorities who spent the past decade targeting marijuana growers in the Sierra Nevada wilderness have turned their attention toward California's agricultural heartland -- the nation's richest farmland -- which they say is the new hot spot for illicit growers, their guns and toxic pesticides thanks to medical marijuana laws.
At a news conference Wednesday, authorities announced results of a summer-long enforcement effort in the state's agricultural region: 175 local and federal arrests, along with 100 guns, $4,869 in cash and 400,000 plants seized across hundreds of thousands of acres.
"These grows are not about medical marijuana," said U.S. Attorney Benjamin Wagner. "They are large amounts cultivated for commercial purposes and sold to people often outside of California."
The crackdown involved federal prosecutors and agents from six sheriff's offices in the southern half of the San Joaquin Valley.
"Make no mistake: This isn't about medicine. This is about money," Kern County Sheriff Donny Youngblood said. "Almost every grower we take down has some connection to a cartel in Mexico. They aren't here to make a little money. They are here to make a lot of money."
Federal authorities said most of the defendants charged in "Operation Mercury" were not Mexican nationals. On Wednesday, the Fresno County Sheriff's Office busted a marijuana grow hidden in a legitimate farming operation owned by people from Southeast Asia.
The move toward growing pot in California's agricultural heartland comes after authorities spent a decade targeting illicit grows in the rugged terrain of the Sierra Nevada. In 2010, more than 5 million plants were seized on public land in California. Fewer than 2.5 million plants were destroyed last year.
Growers moving to the valley floors have attempted to use the state's medical marijuana laws to cultivate openly, cobbling together multiple permits to cultivate on large scales.
During the investigations, federal authorities sent letters to property owners giving them 14 days to eradicate the marijuana seen growing on their property before their land is subject to seizure.
Officials did not know how much the regional crackdown on marijuana had cost, but local sheriffs said they were targeting the large grows because of the criminal element they attract. Many grows are booby-trapped or protected by armed guards.
"As they infiltrate each and every county, it brings a criminal element," Merced County Sheriff Mark Pazin said. "If you use that as the central point you are bringing in the other riffraff. You're bringing in people hooked on this poison. Those are the unintended consequences of drug cartels coming in and procuring acreage in the breadbasket of America."
California, with its temperate weather, lax attitudes toward the plant and laws that allow growing and consumption for medical use, produces most of the marijuana grown in the country. The counties targeted in the crackdown are home to more than 400 commodities and generate the largest farm revenues in the nation.
"We want the Central Valley to be known as America's breadbasket, not as a marijuana-laced-brownie basket," Pazin said.